Breathing is by special gas exchange organs along the side of the body called tracheae and malpighian tubules.

This was a pretty far out idea, since blood-based gas exchange is what other arthropods use (including aquatic ones) but was previously thought to be completely absent in insects, which deliver air directly to their tissues via tracheae.

Although tracheae appear to be compressed synchronously, the shape and direction of compression varies within local tracheal segments, and to a lesser extent, between beetles.

tracheate

Myriapods have been traditionally considered the closest relatives of hexapods, thus implying only one origin of terrestriality for the tracheate lineage, but this view is now challenged by molecular evidence.

The insects are tracheate.

Insects are tracheate arthropods and employ direct transfer of respiratory gases to and from their sites of use and generation via the tracheal system.